Central defender James Tomkins limped out of the game early in the first period, something Allardyce admitted his side failed to adequately cope with.

"The game was very frustrating," he said afterwards. "There is a reason why that happened, none of our centre-backs are fit.

"Losing James Tomkins was a big blow for us. Our coping mechanism was playing four full-backs across the back four.

"That has cost us three points. They did their very best but got caught out. We didn't have enough aerial threat defending corners."

The hectic festive schedule has seen the Hammers play four times in 10 days, and Allardyce conceded his team paid the price for their excessive Christmas workload.

"We showed great fighting spirit in the second half," he added. "We have had two games in 48 hours. We practice on the training ground how to hold onto leads.

"But the players forgot how to deal with West Brom's kick-off and stop them scoring. You can blame anxiety or fatigue, but you can't forget how to deal with them."

(Image: Christopher Lee)

Despite their poor league run West Ham find themselves just two games away from Wembley in the Capital One Cup.

But Allardyce has revealed it is Premier League safety, rather than an unlikely trophy tilt, that is uppermost in his mind.

"Cups don't mean anything any more. We worked our way to the League Cup semi-finals. It doesn't matter, what does is our Premier League status and getting points," he added. "They are secondary in our plight, especially with our injuries.

"I think the deciding factor [of staying up] will not be what January signings we make, but how quickly our injured players come back. If the players missing were fit, we'd have won the game. When you have six, seven players injured it's too much to cope."